According to a press release published by EE Times, Micron is developing a DDR4-compatible hybrid DRAM-NAND cache data faster than the PCIe bus used by other flash cache products.
The move gives flash a new position in the computer memory hierarchy, ahead of today’s solid state drives that ride the PCI Express bus. The Hybrid DIMMs will be more expensive than SSDs but likely offer greater performance with memory access times measured in nano- rather than microseconds.
The hybrid DIMMs use a special controller as the main interface to the processor. They also have a separate flash controller.
Micron is doing its own work enabling hybrid DIMMs under Linux. It expects to roll out that software in time for the DDR4 products.